An Enquiry concerning Human Understanding (World's Classics)

by David Hume

Thus a priori demonstration is limited to the abstract realm of ideas, but only in mathematics are our ideas sufficiently precise to make demonstrative argument genuinely fruitful (E 12.27). The upshot of all this is to limit the worthwhile fields of investigation to mathematics (which is a priori but concerns only relations of ideas) and inductive empirical science (which concerns matters of fact but is uncertain and empirical). Any work that purports to transcend these limits, by establishing matters of fact with demonstrative certainty—what Immanuel Kant would later call ‘synthetic a priori knowledge’—can therefore be roundly condemned, as Hume expresses in his famous concluding paragraph: When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning containing quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion. (E 12.34)